Copyright © 2013 Open Geospatial Consortium.
7 Texas at Austin. This software will be used to demonstrate the processing of SWE
Common encoded GPS data within a web-enabled environment.
6.2 Messaging and file formats within the GPS system
As shown in Fig. 1, the data flowing between various archiving and processing components of the GPS correction system exist in a wide variety of data formats.
Currently, these message streams consist of message structures defined through various documents, some of which have restricted access. Additionally, these streams and the
messages they contain, are being encoded in various formats, including for example, a binary exchange format BINEX, a system-specific XML schema, a HDF5 file format,
text-based formats, and others. Additionally, the message components within each of these formats are inconsistent, even though two messages e.g. FilterPRED and SP3
may contain similar information. Often a processing system is required to read data and output results in multiple formats and to understand the inconsistencies between them.
By forcing different software and processing systems to support multiple message structures and data formats, the current system inhibits the effective use of these data by
1 requiring several format-specific readers and writers to be developed in the appropriate software language i.e. C, C++, Java, Python, etc. required by each
application system, 2 providing inconsistent message structures between the data used or produced by
different processing systems, 3 requiring careful and thus error-prone human interpretation of the data
components based on the documentation provided for each 4 a lack of interoperability with regard to using data designed for or produced by a
different particular processing system 5 discouragement of new and innovative software and processing solutions
This Engineering Report addresses the feasibility of utilizing the OGC SWE Common Data v2.0 standard as a potentially beneficial means of supporting all message and data
streams within future generations of the GPS operational network. In particular, the current effort is focused on the message streams that provide the input to and output from
the processing systems that are responsible for providing improved position and time accuracy within the GPS network. Such processing systems are responsible for ingesting
streams of data consisting of satellite ephemeris, clock information, and satellite health reports over a given time period e.g. five minutes, and then calculating and outputting
improved navigation and timing information for use by the satellites and ultimately the GPS receiver.
8
Copyright © 2013 Open Geospatial Consortium.
6.3 Project Purpose and Goals
